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Appendix VI.

1019

the drill spindle P can be placed at any desired angle, which is
effected by allowing the horizontal slide B to be turned on its
long axis by the worm gear N, while the front saddle D is rotated
in the plane of the paper upon a back saddle c. The saddles are
traversed by the screw w to the required position, and the drive
is through shaft L and mitre gear E to the sleeve F, and thence to
the spindle P. The smaller mitre gear G actuates the feed,
through belt cones H H, worm gear at s, and spur wheels L M ;
hand feed being obtainable in the usual manner by shaft K to the
spur gear. The whole constitutes an exceedingly convenient
design of radial drill.

P. 168. The Square-hole Drilling Machine (Ainley-
Oakes) is a very interesting and remarkable contrivance, for by
its aid true and sharp square or hexagonal holes may be actually
drilled with accuracy. Referring to Fig. 931, a vertical standard
carries a bracketted table x, which may be raised to any con-
venient position by the screw Y and then fixed. Upon this table
are cross slides for adjustment of the work, and a worm gear w
for rotation of the vertical axis of the work table v to any desired
angle. The drill spindle a carries a specially formed tool F, and
is encased in, and driven by, the sleeve E through the mitre gear
c on the outer sleeve D, A being the main driving cone, and B the
driving shaft Upon the sleeve E are formed suitable cams,
shewn in section at a a> which are made to engage within fixed
cam plates at x T when required, such engagement or disengage-
ment being effected by a lowering or raising of the sleeve E by
means of the lever p K and the parallel motion H j, after which p
is fixed on its section plate. The side motion or wobble caused
by the engagement of the sleeve E with the cam plates is allowed
for in the coupling u, which connects the spindle to the feed
screw M, and the feed is obtained in the usual manner by power
through belt gear s, worm gear Q, spindle P, and spur gear N to
the screw M ; or by hand wheel R.

The cam plates for square holes are shewn at z, and three
different sizes at least are supplied, while round holes may be
drilled by the aid of the plates zl; any pair of plates being put in
or out of gear by means of right- and left-handed screws that